Method and apparatus for suspending duct by inserted corner members

ABSTRACT

An air transport duct, and sections of such duct, capable of connection to a support by support members and attachment members formed from two mating members. Each section has two terminal open ends and a flange disposed around each open end for connection to a flange of an adjacent section. Each flange includes two relatively transverse receiving channels adjacent to a corner of the flange, and an insertable corner member positioned into the channels. The corner member is attached to the flange by a load-bearing connection, and can support a predetermined portion of a weight of the duct by connection of the corner member to a first mating member connectable to a second mating member secured to a corresponding support member. A method of connecting a duct to a support by forming a load-bearing connection between a corner member and a flange.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Application No. 61/478,300,filed on Apr. 22, 2011, the complete disclosure of which is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to the field of heating, ventilating, andair conditioning ductwork and more particularly to a method andapparatus for connecting ductwork to a support.

BACKGROUND OF THE INVENTION

Buildings such as factories, office buildings, and homes typicallyrequire the transport of air to, within and from such buildings. Thismay involve the removal of stale air, as well as the distribution of airconditioned in a variety of ways, including heating, cooling, adding orremoving moisture and filtration, to name some examples. The technologyand systems related to the conditioning and distribution of air inbuildings are generally referred to by the acronym HVAC (Heating,Ventilating, and Air Conditioning).

In some HVAC systems, ducts may be used to remove air or distributeconditioned air throughout a building. The ducts used in a HVAC systemare often collectively referred to in the art as “ductwork”, andindividually as “ducting”. Some HVAC systems may also incorporate theuse of fans or other mechanisms to force the air through the ductwork,as well as components to condition the air, such as furnaces orhumidifiers.

One common type of ducting is a rectangular duct formed from sheetmetal, commonly referred to in the art as “rectangular metal duct”. Thistype of duct is formed by constructing separate, hollow, and elongatedsections of duct, and connecting same together so as to form ductworkthrough which air may be transported.

As air must typically be transported throughout a building, ductwork isalso typically installed throughout a building, preferably inunobtrusive locations. Therefore, one common installation procedure isto suspend ducting from elevated supports, such as overhead pipes or thesurfaces of ceilings.

There are a number of ways known in the art to suspend rectangular metalducts from a support. Most commonly, one end of a length of steel wire,steel strap or threaded rod may be anchored to a support using any of avariety of mechanisms well known in the art. The other end of the lengthof steel wire, steel strap or threaded rod may then be connected to theduct to provide support for the duct. Steel wire and steel straps maydirectly support the duct by encircling the duct, whereas threaded rodsare generally used in conjunction with a cradle bar, also known in somecircumstances as a support channel, that supports the duct from below.Cradle bars are widely used to suspend rectangular metal ducts, andgenerally involve supporting a duct from below at regular intervals witha cradle bar, with each terminal end of each cradle bar being connectedto one end of a threaded rod, with the other end of the threaded rodbeing anchored to supports such as an overhead pipe or ceiling surface.Although steel wire may be employed to directly support a duct asaforesaid, steel wire may also be used in conjunction with cradle barsif so desired.

Unfortunately, there are problems associated with prior art methods ofsupporting rectangular metal duct. These include high labour andmaterial costs and the structural integrity of the support methods. Forinstance, it has been known with steel wire that the latter can at timescut into the sheet metal wall of a duct which it directly supports,depending on weight considerations. With regard to cradle bars, lengthsof cradle bars must typically be cut to size to correspond to the widthof the particular ductwork being supported, thereby increasing thelabour costs of their manufacture or installation. Also with regard tocradle bars, the lengths of supporting steel wire or rod which must bedeployed in installation must be long enough to reach the bottomsupported surface of the affected ductwork, given that the cradle barsare typically located and support the ductwork from underneath same.Accordingly, there is a need for a method, and apparatus, for connectinga duct to a support, which is intended to assist with eliminating oralleviating some or all of the aforementioned problems associated withthe prior art approaches.

SUMMARY OF THE INVENTION

In one aspect of the present invention there is provided a method ofconnecting an elongate air transport duct to a support by means of aplurality of support members located between the duct and the support,the duct having a generally rectangular cross-section and comprising aplurality of interconnected duct sections, each of the duct sectionscomprising two terminal open ends and a flange disposed around each ofthe open ends for abutting connection to the flange of an adjacent ductsection of the duct, each the flange comprising a first receivingchannel adjacent to a first corner thereof, a second receiving channelthat is generally transverse to the first receiving channel and adjacentthe first corner, and a first insertable corner member positioned intothe first receiving channel and into the second receiving channel, themethod comprising the step of: forming a load-bearing connection betweeneach the first insertable corner member and at least one of the firstreceiving channel and the second receiving channel into which each thefirst inserted corner member is positioned, such that each the firstinsertable corner member is thereafter capable of supporting apredetermined portion of a weight of the duct by connection of each thefirst insertable corner member to one of the plurality of supportmembers.

In another aspect of the present invention there is provided a ductsection of an air transport duct that is capable of connection to asupport by means of a plurality of support members located between theduct and the support, the duct section having a generally rectangularcross-section and comprising two terminal open ends and a flangedisposed around each of the open ends for abutting connection to theflange of an adjacent duct section of the duct, each the flangecomprising a first receiving channel adjacent to a first corner thereof,a second receiving channel that is generally transverse to the firstreceiving channel and adjacent the first corner, and a first insertablecorner member positioned into the first receiving channel and into thesecond receiving channel, wherein the first insertable corner member isattached to at least one of the first receiving channel and the secondreceiving channel by means of a load-bearing connection therebetween,such that the first insertable corner member is thereafter capable ofsupporting a predetermined portion of a weight of the duct by connectionof the first insertable corner member to one of the plurality of supportmembers.

In another aspect of the present invention there is provided an elongateair transport duct for connecting to a support by means of a pluralityof support members located between the duct and the support, the ducthaving a generally rectangular cross-section and comprising a pluralityof interconnected duct sections, each of the duct sections comprisingtwo terminal open ends and a flange positioned around each of the openends for abutting connection to the flange of an adjacent duct sectionof the duct, each the flange comprising a first receiving channeladjacent to a first corner thereof, a second receiving channel that isgenerally transverse to the first receiving channel and adjacent thefirst corner, and a first insertable corner member positioned into thefirst receiving channel and into the second receiving channel, whereineach the first insertable corner member is attached to at least one ofthe first receiving channel and the second receiving channel into whicheach the first inserted corner member is positioned by means of aload-bearing connection therebetween, such that each the firstinsertable corner member is capable of supporting a predeterminedportion of a weight of the duct by connection of each the firstinsertable corner member to one of the plurality of support members.

In another aspect of the present invention there is provided anattachment member for connecting an air transport duct to a support bymeans of a support member located between the duct and the support, theattachment member having first and second mating members that areconnectable to one another, the first mating member providing a firstconnector for securing the attachment member to a duct section of theduct, the second mating member providing a second connector for securingthe attachment member to the support member.

In another aspect of the present invention there is provided a method ofconnecting an elongate air transport duct to a support by means of aplurality of support members located between the duct and the support,the duct having a generally rectangular cross-section and comprising aplurality of interconnected duct sections, each of the duct sectionscomprising two terminal open ends and a flange disposed around each ofthe open ends for abutting connection to a flange of an adjacent ductsection of the duct, each the flange comprising a first flange walladjacent to a first corner thereof, a second flange wall that isgenerally transverse to the first flange wall and adjacent the firstcorner, and a first corner member positioned adjacent to the firstflange wall and to the second flange wall, the method comprising thesteps of: forming a load-bearing connection between each the firstcorner member and at least one of the adjacently positioned first flangewall and the second flange wall, such that each the first corner memberis thereafter capable of supporting a predetermined portion of a weightof the duct by connection of each the first corner member to one of theplurality of support members; and forming a connection between at leastone of the first insertable corner members to one of the plurality ofsupport members.

In another aspect of the present invention there is provided an airtransport duct for connecting to a support by means of at least onesupport member located between the duct and the support, the ductcomprising at least one duct section, each of the at least one ductsection comprising two terminal open ends and a flange positioned aroundeach of the open ends for abutting connection to the flange of acorresponding duct section, each the flange comprising a first receivingchannel adjacent to a first corner thereof, a second receiving channelthat is generally transverse to the first receiving channel and adjacentthe first corner, and a first insertable corner member positioned intothe first receiving channel and into the second receiving channel,wherein each the first insertable corner member is attached to at leastone of the first receiving channel and the second receiving channel intowhich each the first inserted corner member is positioned by means of aload-bearing connection therebetween, such that each the firstinsertable corner member is capable of supporting a predeterminedportion of a weight of the duct by connection of each the firstinsertable corner member to one of the at least one support member.

Additional aspects and advantages of the present invention will beapparent in view of the description which follows. It should beunderstood, however, that the detailed description, while indicatingembodiments of the invention, are given by way of illustration only,since various changes and modifications within the spirit and scope ofthe invention will become apparent to those skilled in the art from thisdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to embodiments thereof, the invention will next bedescribed in relation to the drawings, which are intended to benon-limiting examples of various embodiments of the present invention,in which:

FIG. 1 is a perspective view of interconnected and suspended ductsections forming a portion of a duct, according to an illustrativeembodiment of the present invention;

FIG. 2 is a perspective view of a duct section from the duct of FIG. 1,showing a flange formed along the periphery of each terminal endthereof;

FIG. 3 is an exploded partial view of a corner of the duct section ofFIG. 2 with a corner member intended for engagement with two adjacentchannels of the duct section;

FIG. 4A is a partial cross-sectional view of the corner of the ductsection of FIG. 2, wherein the corner member is depicted in itsengagement position with a prior art transverse duct flange (“TDF®”)style channel formed along the periphery of a terminal end of the ductsection;

FIG. 4B is a partial cross-sectional view of the corner of the ductsection of FIG. 2, wherein the corner member is depicted in itsengagement position with a prior art transverse duct connector (“TDC®”)style channel formed along the periphery of a terminal end of the ductsection;

FIG. 4C is a partial cross-sectional view of the corner of FIG. 4Bwherein a leading edge of the TDC® style channel is crimped to maintainthe corner member in contact with its two corresponding adjacentchannels of the duct section;

FIG. 5A is a partial perspective view of the corner and corner member ofFIG. 4B, showing metal formed load-bearing connections for attaching thecorner member to its two corresponding adjacent channels of the ductsection;

FIG. 5B is another partial perspective view of the corner and cornermember of FIG. 5A, viewed in a direction opposite to that of FIG. 5A;

FIGS. 6A, 6B, and 6C are cross-sectional views depicting the stepsinvolved in the creation of a first type of metal formed load-bearingconnection of FIG. 5A and FIG. 5B;

FIGS. 7A, 7B, and 7C are cross-sectional views depicting the stepsinvolved in the creation of a second type of metal formed load-bearingconnection of FIG. 5A and FIG. 5B;

FIG. 8 is an exploded partial view of two interconnected duct sectionsfrom the duct of FIG. 1;

FIG. 9 is an exploded partial sectional view of the interconnected ductsections of FIG. 8;

FIGS. 10A, 10B, 10C, and 10D are multiple views of a female matingmember for connection to a corner member that has been inserted into itscorresponding adjacent channels of a duct section and connected to thechannels according to FIGS. 5A and 5B;

FIGS. 11A, 11B, 11C, and 11D are multiple views of a male mating memberfor connection to the female mating member of FIGS. 10A, 10B, 10C, and10D;

FIG. 12A is a perspective view of the female mating member of FIGS. 10A,10B, 10C, and 10D connected to steel wire;

FIG. 12B is a perspective view of the female mating member of FIGS. 10A,10B, 10C, and 10D connected to steel strap; and

FIG. 12C is a perspective view of the female mating member of FIGS. 10A,10B, 10C, and 10D interconnected with the male mating member of FIGS.11A, 11B, 11C, and 11D, showing the male mating member connected to athreaded rod;

DETAILED DESCRIPTION OF THE INVENTION

According to embodiments of the present invention, various apparatus andmethods for connecting ducting at mating corners of its constituent ductsections to existing means of support such as wires, rods or straps willnext be described in detail, including processes for metal formedload-bearing attachment of inserted corner members to correspondingadjacent channels of the duct section with which the inserted cornermembers are held in contact, and a two-piece attachment membercomprising a male mating member and a female mating member forconnecting the inserted and attached corner members to existing means ofsupport.

With reference to FIG. 1, there is illustrated a plurality ofinterconnected and suspended duct sections 102, 104, 106, 108 that forma portion of a duct 100, with each duct section constituting a separate,hollow and elongated rectangular metal section of duct through which airmay be transported.

FIG. 2 depicts duct section 104 in isolation, this duct section isgenerally representative of duct sections such as duct sections 102,106, 108. Duct section 104 comprises a body 218 and flanges 190, 192,each described in more detail below. In this embodiment of the presentinvention, duct section 104 is formed sheet metal, but in otherembodiments of the present invention, other materials well known in theart such as plastic, wood, and fibreglass may be used in whole or inpart. Also, in this embodiment of the present invention, each ductsection is elongated and rectangular, but in other embodiments of thepresent invention, other shapes of duct sections may be used, such asduct sections with a circular cross-section.

Body 218 of duct section 104 may be formed from sheet metal by anynumber of methods and apparatus well known in the art, such as themethods and apparatus readily available from Iowa Precision Industriesof Cedar Rapids, Iowa, and including the Pro-Fabriduct® automatedrectangular duct forming and fabricating lines. Body 218 has four panels110, 112, 114, 116 arranged to form a rectangular prism with twoopposing and open sides 118, 120. For ease of reference and withoutlimiting the generality of any description, panel 110 and its outwardlyfacing direction will respectively be referred to as the “top” panel andthe “up” direction and panel 116 and its outwardly facing direction willrespectively be referred to as the “bottom” panel and the “down”direction.

Panels 110, 112 meet at a bend 122 that extends between sides 118, 120.Additional bends 124, 126, 128 extend between sides 118, 120 and arerespectively located where panels 110, 114, panels 114, 116, and panels112, 116 meet. As body 218 is typically formed from a single sheet ofsheet metal, an arbitrary three of bends 122, 124, 126, 128 are rightangle bends in the sheet metal, whereas the remaining fourth bend isformed by joining at a right angle the edges of the correspondingpanels. Methods to join at a right angle two edges of sheet metal arewell known in the art, such as by means of a Pittsburgh lock (notshown).

Flange 190 is a rectangular frame that surrounds side 120. flange 190has four elongated channels 194, 196, 198, 200 that each extend thelength of one edge of side 120 to jointly form a rectangular framewithout corners, and four L-shaped corner members 152, 154, 156, 158that each respectively engage with two of the channels at theabove-noted missing corners so that a complete rectangular frame isformed. Specifically, corner member 152 engages with channels 194, 196,corner member 154 engages with channels 196, 200, corner member 156engages with channels 194, 198, and corner member 158 engages withchannels 198, 200. Flange 192 similarly comprises four elongatedchannels 202, 204, 206, 208 and four L-shaped corner members 160, 162,164, 166.

The aforesaid channels, corner members and their manner of engagementare described in more detail with reference to FIG. 3. FIG. 3 depicts asingle corner of duct section 104 before corner member 152 engages withchannels 194, 196 and is generally representative of the other channelsand corner members of duct section 104, and their manner of engagement.

Corner member 152 may be formed from sheet metal by any number ofmethods well known in the art such as stamping. Corner member 152comprises legs 182, 180 that are disposed at a right angle about corner188 to form an L-shape. An opening 262 is positioned in corner 188. Whencorner member 152 is respectively received by and engaged with acorresponding channel, such as channels 194, 196, the channel surface184 of corner member 152 abuts with the flange wall of its correspondingchannel, in that channel surface 184 is a flat side of corner member 152that contacts the corresponding opposed surface, such as inside surfaces193, 195 of flange walls 197, 199 of channels 194, 196. As will bedescribed in more detail below, channels 194, 196 also each have a flatflange surface on the side of flange walls 197, 199 opposite insidesurfaces 193, 195 configured to mate with another flange surface ofanother channel of another duct section. An exterior surface 186 islocated on the opposite side of corner member 152 relative to channelsurface 184 and faces away from the channel when corner member 152 isengaged therewith. Corner member 152 may additionally have upstandingflanges 176, 178 or other suitable reinforcement well known in the art.

Corner member 152 may be formed to be stackable with another cornermember. In this embodiment of the present invention, corner member 152has upstanding projections 168, 170, 172, 174 that project away fromexterior surface 186 and may be individually formed by stamping a tabout of the sheet metal used to form corner member 152 and bending thetab so that it is configured to project away from exterior surface 186.When multiple corner members are stacked, the upstanding projections ofa stacked corner member engages the channel surface of an adjacentstacked corner member, and operate to support and space apart thestacked corner members.

In this embodiment of the present invention, corner member 152 may be acorner member available from a variety of suppliers further to a licenseto U.S. Pat. No. 5,342,100 to Goodhue, and compatible with theCornermatic® automatic corner inserter readily available from IowaPrecision Industries of Cedar Rapids, Iowa. In other embodiments of thepresent invention, particularly where each duct section is notrectangular, corner member 152 may not be configured to form an L-shape,but rather, may, for example, form a V-shape, or even an arc.

With reference to FIG. 3, FIG. 4A, and FIG. 4B, in this embodiment ofthe present invention, channels 194, 196 are integrally formed with body218. Channels 194, 196 first extend perpendicularly outwardly from,respectively, panels 112, 110 to form flange walls 197, 199, then extendin a direction parallel to and towards the center of, respectively,panels 112, 110, before doubling-back. FIG. 4A depicts channel 196wherein it has doubled-back by folding upon itself inwardly towardspanel 110 and therefore corresponds to prior art TDF® style flanges.FIG. 4B shows channel 196 wherein it has doubled-back by folding uponitself outwardly away from panel 110 and therefore corresponds to priorart TDC® style flanges. Again with reference to FIG. 3, FIG. 4A, andFIG. 4B, channel 196 has a flange surface 212 on one side of flange wall199 that, as discussed in more detail below, is configured to mate withanother flange surface of another channel of another duct section.Channels 194, 196 also have cavities 216, 214 circumscribed and definedby channels 194, 196 and panels 112, 110, respectively.

In this embodiment of the present invention, channels 194, 196 may beintegrally formed from the same sheet of sheet metal as body 218.Methods and apparatus for forming duct section 104 with channels 194,196 are readily available from Iowa Precision Industries of CedarRapids, Iowa, and also further described in U.S. Pat. No. 4,466,641 toHeilman et al. and U.S. Pat. No. 4,579,375 to Fischer et al. In otherembodiments of the present invention, channels may be separately formedand connected to body 218 by means well known in the art such as weldingor riveting. Related methods and apparatus for separately formingchannels and connecting such channels to a body of a duct are readilyavailable from Ductmate Industries, Inc. of Charleroi, Pa., and alsofurther described in U.S. Pat. No. 4,218,079 to Arnoldt.

Leg 180 of corner member 152 is configured to be engaged with channel194 by inserting leg 180 into cavity 216. Leg 182 of corner member 152is similarly configured to be engaged with channel 196 by inserting leg182 into cavity 214. Once so inserted, corner member 152 is engaged withchannels 194, 196 to form part of flange 190. Notably, the empty cornerbetween channels 194, 196 is filled with corner member 152.

In some embodiments of the present invention, corner member 152 isengaged with channels 194, 196 by means of manual insertion. Otherembodiments of the present invention may use well known methods andapparatus disclosed for automatically engaging corner members withchannels. This includes the Cornermatic® automatic corner inserterreadily available from Iowa Precision Industries of Cedar Rapids, Iowa,and methods and apparatus further disclosed by U.S. Pat. No. 5,321,880to Goodhue and U.S. Pat. No. 5,283,944 to Goodhue.

While the original form of channels 196, 194 somewhat retain legs 182,180 in cavities 214, 216, additional retention means are typicallyemployed. In some embodiments of the present invention, portions ofchannels 196, 194 may be crimped over legs 182, 180 once corner member152 has been engaged with channels 196, 194. With reference toillustrative FIG. 4C, the leading edge of channel 196 is crimped overleg 182 so as to better retain leg 182 in cavity 214.

Another drawback is that crimping does not always retain legs 182, 180in cavities 214, 216 during typical use of duct section 104. Forexample, it is typical for duct sections to be formed at a commercialduct shop, including the formation of completed flanges comprising inpart inserted corner members. One or more duct sections may be connectedtogether, and subsequently transported to a construction site forinstallation. It is common for corner members to become disengagedduring transport and to need to be manually re-inserted at theconstruction site, despite the use of crimping.

With reference to FIG. 5A and FIG. 5B, in this embodiment of the presentinvention, corner member 152 is attached to its corresponding flangewalls 197, 199 while abutting its corresponding inside surfaces 193, 195within channels 194, 196 by means of one or more connections, forinstance four, metal formed load-bearing connections 224, 226, 228, 230,described in greater detail below. Connections 224, 226 attach leg 180to the corresponding flange wall 197 while abutting corresponding insidesurface 193 of channel 194. Connections 228, 230 similarly attach leg182 to the corresponding flange wall 199 while abutting correspondinginside surface 195 of channel 196. In this embodiment, connections 224,226, 228, 230 are formed after corner member 152 has been engaged withchannels 194, 196 as previously described. As connections 224, 226, 228,230 are metal formed and load-bearing, the above-described crimping ofchannels 194, 196 may be rendered redundant as a means to retain cornermember 152 in engagement with channels 194, 196 and as such, the personof skill in this art may very well choose not to deploy the crimpingtechnique as foresaid in conjunction with the present invention.Similarly, whereas the above-described channels first extendperpendicularly outwardly from the panels to form flange walls, thenextend in a direction parallel to and towards the center of the panels,before doubling-back, in some embodiments of the present invention, theextending in a direction parallel to and towards the center of thepanels, before doubling-back, may not be required. In suchcircumstances, the channels may comprise only a flange wall to whichcorner members may be attached with the above-described connections, butthe channels may not otherwise engage the corner members.

As described in more detail below, in one embodiment of the presentinvention, a duct 100 may be supported from existing means of support byconnecting the existing means of support directly or indirectly to oneor more corner members such as corner member 152. These corner members,such as corner member 152, as described above, are engaged withcorresponding channels, such as channels 194, 196, of duct sections,such as duct sections 102, 104, 106, 108 by means of load-bearingconnections, such as connections 224, 226, 228, 230. In this context,these connections 224, 226, 228, 230 are termed herein as load-bearingsince these connections collectively bear the load of supporting theduct.

In this embodiment of the present invention, connections 224, 226, 228,230 are obtained by cold-forming a press joint in order to clinchtogether in a metal forming operation the corner members, such as cornermember 152, and the flange walls of corresponding channels, such asflange walls 197, 199 of channels 194, 196. Such clinching results in amechanical interlock between the sheet metal corresponding to the cornermembers, such as corner member 152, and the sheet metal corresponding tothe flange walls of the channels, such as flange walls 197, 199 ofchannels 194, 196, and may involve the use of drawing, lancing,expanding, and otherwise deforming sheet metal to form said mechanicalinterlock.

For instance, the connections 224, 226, 228, 230 may be obtained by wayof prior-art Lance-N-Loc® joints, namely, a metal forming technologyreadily available from BTM Corporation of Marysville, Mich., and furtherdescribed in U.S. Pat. No. 5,150,513 to Sawdon and U.S. Pat. No.5,177,861 to Sawdon. FIG. 6A, FIG. 6B, and FIG. 6C depict creatingrepresentative connection 224 between leg 180 and flange wall 197 ofchannel 194. In FIG. 6A, and with reference to FIG. 3, FIG. 4A, and FIG.4B, leg 180 is engaged with channel 194 by having been inserted intocavity 216. Channel surface 184 directly abuts the corresponding insidesurface 193 of channel 194. A clamp (not shown) may be used to minimizethe gap between leg 180 and inside surface 193 of channel 194, and totemporarily secure together leg 180 to flange wall 197 of channel 194while forming connection 224.

With reference to FIG. 6B, leg 180 and flange wall 197 of channel 194are lanced along two parallel planes 326, 328 by a die of rectangularcross-section (not shown), forming a lanced portion 324 disposed betweenparallel planes 326, 328 and wherein each lance corresponds to thelength of the rectangular cross-section of the die (not shown). Afterlancing, lanced portion 324 is drawn through the thickness of leg 180and flange wall 197 of channel 194 in the direction from flange wall 197of channel 194 to leg 180 by the die (not shown), thereby forming thebeginnings of a protrusion 320. Lanced portion 324 remains integrallyconnected to leg 180 and flange wall 197 of channel 194 along the widthof the rectangular cross-section of the die (not shown). A cavity 330 inleg 180 and flange wall 197 of channel 194 is formed, when viewed fromthe side of flange wall 197 of channel 194.

With reference to FIG. 6C, lanced portion 324 is expanded beyond thewidth of parallel planes 326, 328 by compressing lanced portion 324 witha die (not shown) against an anvil (not shown), thus completing theformation of protrusion 320. As protrusion 320 extends beyond the widthof parallel planes 326, 328, protrusion 320 is restricted from beingretracted back through the thickness of leg 180 and flange wall 197 ofchannel 194. As leg 180 and flange wall 197 of channel 194 both remainintegrally connected to lanced portion 324, leg 180 and flange wall 197of channel 194 are restricted from being separated, and connection 224has interconnected leg 180 and channel 194.

In another embodiment of the present invention, connections 224, 226,228, 230 are prior-art Tog-L-Loc® joints, namely, a metal formingtechnology readily available from BTM Corporation of Marysville,Michigan, and further described in U.S. Pat. No. 5,150,513 to Sawdon andU.S. Pat. No. 5,177,861 to Sawdon. FIG. 7A, FIG. 7B, and FIG. 7C depictcreating representative connection 224 between leg 180 and flange wall197 of channel 194. In FIG. 7A, and with reference to FIG. 3, FIG. 4A,and FIG. 4B, leg 180 is engaged with channel 194 by having been insertedinto cavity 216. Channel surface 184 directly abuts the correspondinginside surface 193 of channel 194. A clamp (not shown) may be used tominimize the gap between leg 180 and inside surface 193 of channel 194,and to temporarily secure together leg 180 to flange wall 197 of channel194 while forming connection 224.

With reference to FIG. 7B, leg 180 and flange wall 197 of channel 194are drawn through the thickness of leg 180 and flange wall 197 ofchannel 194 in the direction from flange wall 197 of channel 194 to leg180 by a die (not shown) to form drawn portion 334. Drawn portion 334remains integrally connected to leg 180 and flange wall 197 of channel194 as neither leg 180 nor flange wall 197 of channel 194 is pierced.The die is circular in cross-section, and so drawn portion 334 issimilarly circular from a top view (not shown). A cavity 332 in leg 180and flange wall 197 of channel 194 is formed, when viewed from the sideof flange wall 197 of channel 194, and the beginnings of a protrusion322 extends from leg 180 corresponding to drawn portion 334.

With reference to FIG. 7C, drawn portion 334 is expanded beyond theoriginal diameter of drawn portion 334 by compressing drawn portion 334with a die (not shown) against an anvil (not shown), thus completing theformation of protrusion 334. Leg 180, flange wall 197 of channel 194,and drawn portion 334 are therefore in an interlocking configurationwherein leg 180 and flange wall 197 of channel 194 are restricted frombeing separated, and connection 224 has interconnected leg 180 andchannel 194.

In some embodiments of the present invention, it may be advantageous forconnections 224, 226, 228, 230 to be Lance-N-Loc®) joints as opposed toTog-L-Loc® joints. In particular, it has been found that tooling forcreating Lance-N-Loc® joints is typically compatible with a wider rangeof sheet metal thicknesses, an advantage as ducting may be formed fromsheet metal of a variety of thicknesses.

Further, duct sections are generally interconnected by mating flangesurfaces of a first duct section with flange surfaces of a second ductsection, as described in more detail below. Accordingly, it is typicallyconsidered to be advantageous for flange surfaces, such as flangesurface 212, to be flush so as to improve the seal and fit between twoflange surfaces. As described above, both Tog-L-Loc® and Lance-N-Loc®joints result in protrusions, such as protrusions 320, 322. An advantageof a metal formed load-bearing joint of the type described herein isthat the mating surfaces of flanges, such as flanges 190, 192, can berendered free of protrusions so that a flush connection of the opposedflanges of adjacent duct sections may be obtained by causing theprotrusions to emanate from the corner member side, namely, the exteriorsurface of a corner member, such as exterior surface 186 of cornermember 152. A further characteristic of Tog-L-Loc® joints is that thethickness of the metal on the side from which the protrusion, such asprotrusion 322, emanates must be less than or equal to the thickness ofthe metal on the opposite side thereof, which is not a characteristic ofLance-N-Loc® joints. Accordingly, as corner members are typicallyproduced in a single thickness, use of Tog-L-Loc® joints with ductingformed from sheet metal thinner than standard corner members wouldrequire forming connections in the opposite direction than thatdescribed above. This may disadvantageously result in a protrusionextending out from a flange surface and potentially diminishing theefficacy of the seals between two flange surfaces. Those of skill inthis art will understand that the particular metal formed load-bearingconnection will be selected based on the thickness of the cornermembers, such as corner member 152, and the thickness of the flangewalls of channels, such as flange walls 197, 199 of channels 194, 196,so that the protrusions obtained therefrom, such as protrusions 320,322, emanate from a surface other than that of the mating flangesurface, such as flange surface 212.

With reference to FIG. 5A and FIG. 5B, in this embodiment of the presentinvention, corner member 152 is interconnected to channels 194, 196 byfour Lance-N-Loc® joints constituting connections 224, 226, 228, 230. Inother embodiments of the present invention, corner members may beinterconnected to channels by a different number of connections.Similarly, in other embodiments of the present invention, other types ofconnections may be used to interconnect corner members and channels.Alternatives are well-known to those skilled in the art, and may includethe use of rivets, bolts, welding, adhesives, and load-bearing crimping.Different types of connections may also be used in combination, both tointerconnect a single corner member, or as between different cornermembers. In some embodiments, some corner members may not need to beinterconnected with channels by means of any connection at all. Thespecific number, type, and combination of the connections will beapparent to the person skilled in the art.

Returning to FIG. 1 and FIG. 2, as noted previously, the abovedescription of duct section 104 is generally representative of ductsections 102, 106, 108.

So as to form the interconnected duct sections forming a portion of duct100 shown by FIG. 1, duct sections are pairwise interconnected.Specifically, a first open side of duct section 102 is mated to a firstopen side of duct section 104 and duct sections 102, 104 areinterconnected as described below. In turn, a second open side of ductsection 104 is mated to a first open side of duct section 106 and ductsections 104, 106 are interconnected as described below. Finally, asecond open side of duct section 106 is mated to a first open side ofduct section 108 and duct sections 106, 108 are interconnected asdescribed below. Once duct sections 102, 104, 106, 108 areinterconnected as described above, air may be transported through thisportion of duct 100.

FIG. 8 and FIG. 9 are exploded partial views of interconnected ductsections 104, 106 and are generally representative of the manner inwhich duct sections are interconnected.

Duct section 104 comprises in part body 218 and flange 192. Duct section106 similarly comprises in part a body 220 and a flange 246. Flanges192, 246 are of similar dimension and shape, namely, as described above,a rectangular frame surrounding open sides of duct sections 104, 106,respectively. Flanges 192, 246 are also of similar construction, againas described above, each comprising four channels and four cornermembers engaged therewith.

To interconnect duct sections 104, 106, duct sections 104, 106 are firstpositioned in close proximity so that flanges 192, 246 correspondinglyabut. Specifically, each channel and each corner member of flange 192abuts an equivalent channel or corner member of flange 246, and viceversa. The flange surfaces of abutting channels face one another, andsimilarly, the channel surfaces of abutting corner members are facingone another. As discussed above with reference to FIG. 3, each cornermember has an opening positioned in the corner that the legs of thecorner member are disposed at a right angle about to form an L-shape.Accordingly, when duct sections 104, 106 are positioned in closeproximity so that flanges 192, 246 correspondingly abut, openings 260,264 are correspondingly adjacent, openings 266, 268 are correspondinglyadjacent, and openings 270, 272 are correspondingly adjacent. Forclarity, the fourth corner members (not shown) of each of flanges 192,246 have similarly correspondingly adjacent openings.

Once duct sections 104, 106 are positioned in close proximity so thatflanges 192, 246 correspondingly abut, corner bolts and corner nuts areused to firmly interconnect duct sections 104, 106. Specifically, acorner bolt 248 is inserted through openings 266, 268, mated with acorner nut 254, and corner bolt 248 and corner nut 254 are tightened.Corner bolts 250, 252 are similarly respectively inserted throughopenings 260, 264 and openings 270, 272, respectively mated with cornernuts 256, 258, and respectively tightened. A corner bolt and a cornernut may be similarly used to connect the openings of the fourth cornermember (not shown) of each of flanges 192, 246. As the four corners offlanges 192, 246 are each firmly connected together by theabove-described use of corner bolts and corner nuts, duct sections 104,106 are also firmly interconnected. For ease of reference,interconnected flanges 192, 246 and additional related members such ascorner bolts and corner nuts are collectively referred to as a ductjoint 132. Duct sections 102, 104 are interconnected by a similarlyconstructed duct joint 130, and duct sections 106, 108 areinterconnected by a similarly constructed duct joint 134.

The skilled person in the art will appreciate that there are suitablealternatives to connecting correspondingly abutting corner members,including, for example, rivets and ties.

Representative duct joint 132 may also optionally include a gasket 232,also known in some circumstances as a sealant. Gasket 232 is placedbetween flanges 192, 246 so as to improve the seal of duct joint 132 andtherefore reduce the leakage of air through duct joint 132 duringoperational use of duct 100 to transport air. Gasket 232 generallycorresponds to the shape and dimensions of flanges 192, 246. Gasket 232may be pre-manufactured to correspond to the shape and dimensions offlanges 192, 246; alternatively, gasket 232 may be manually shaped tocorrespond to the shape and dimensions of flanges 192, 246 duringinstallation of gasket 232. In some embodiments of the presentinvention, gasket 232 may have openings to allow corner bolts to passthrough; alternatively, gasket 232 may be constructed and positioned sothat corner bolts do not pass through gasket 232. Gasket 232 may beformed from a variety of materials, including, for example, putty,sealant, caulting, rubber or foam.

Clips (not shown) may also be optionally placed over the channels offlanges 192, 246 forming duct joint 132. As discussed above, it may bedesirable to reduce the leakage of air through duct joint 132. In theembodiment described above with reference to FIG. 8 and FIG. 9, flanges192, 246 are interconnected at the corner members of flanges 192, 246.Accordingly, the pressure between flanges 192, 246 may be the greatestat the corner members, and potentially less at other locations alongflanges 192, 246 such as the midpoint of the channels of flanges 192,246. In some circumstances, there may potentially be a poorer seal atareas of lower pressure. Accordingly, clips (not shown) may beoptionally placed over part or all of the channels of flanges 192, 246so as to improve the seal of duct joint 132 and therefore reduce theleakage of air through duct joint 132 during operational use of duct 100to transport air.

Representative duct joint 132 may also optionally include one or morefemale mating members, as discussed in more detail below.

Returning to FIG. 1, the depicted interconnected duct sections forming aportion of duct 100 are suspended. As will next be described in detail,in this embodiment of the present invention, two-piece attachmentmembers comprising a male mating member and a female mating memberconnect one or more inserted and secured (as per the metal formedload-bearing connections described above) corner members to existingmeans of support.

With reference to FIG. 10A, FIG. 10B, FIG. 10C, and FIG. 10D, a femalemating member 276 is depicted corresponding to one embodiment of thepresent invention. Female mating member 276 may be formed from sheetmetal using methods well-known in the art such as stamping. Femalemating member 276 comprises a tab 284 and a body 286 depending therefromby means of an optional ledge 282, as described in more detail below.

Body 286 may be generally rectangular in shape and positionedtherewithin may be an opening 280. Opening 280 may be rectangular inshape and is configured to allow a hook of a male mating member to passtherethrough (such as a hook 292 as described below). Opening 280 may bepositioned generally in the center of body 286 and body 286 may beapproximately double the width and length of opening 280.

Tab 284 may be approximately square in shape and positioned therewithinmay be a corner opening 274. Corner opening 274 is configured to allow acorner bolt to pass therethrough (such as corner bolt 248 with referenceto FIG. 8). Corner opening 274 may be positioned generally in the centerof tab 284 and tab 284 may be sized slightly larger than corner opening274. The width of tab 284 may be approximately half the width of body286.

Tab 284 and body 286 may be delineated by means of rectangular shapedledge 282 so that tab 284 and body 286 lie in parallel planes andwherein ledge 282 lies in a perpendicularly transverse plane to theparallel planes. Ledge 282 depends from tab 284 along the entire widthof tab 284 and their intersecting surfaces together form an approximateninety-degree angle. Ledge 282 further depends from body 286 along thewidth of body 286 and their intersecting surfaces together form anapproximate ninety-degree angle. With reference to FIG. 10C, theapproximately equal width of ledge 282 and tab 284 may be approximatelyhalf the width of body 286. Ledge 282 may depend from body 286 so thatledge 282 and tab 284 are aligned with one lengthwise side of body 286.Also with reference to FIG. 10C, tab 284, body 286, and ledge 282 may beconfigured so that tab 284 and body 286 project away from ledge 282 inopposing directions, so as to arrange tab 284, body 286, and ledge 282in a stepped fashion.

In the depicted embodiment of the present invention, a corner 278 may beremoved from body 286 so that, in some circumstances, female matingmember 276 may be better handled, installed, or manufactured. As ledge282 may depend from body 286 along approximately one-half of a widthwiseside of body 286, as described above, removed corner 278 may be thecorner of body 286 that shares this widthwise side of body 286.

As noted above, tab 284 and body 286 depend from ledge 282 so that tab284 and body 286 lie in parallel planes. The depth of ledge 282therefore determines the distance between the parallel planes that tab284 and body 286 lie in. In one embodiment of the present invention,ledge 282 causes tab 284 and body 286 to be separated approximately bythe thickness of the sheet metal from which female mating member 276 isconstructed. In another embodiment of the present invention, ledge 282may not be present so that tab 284 and body 286 lie in the same plane.

With reference to FIG. 1, FIG. 8, and FIG. 9, duct joint 132 mayoptionally include female mating members 234, 236. The followingdescription in regard to female mating member 234 is illustrative andgenerally representative of the interaction between a female matingmember and a duct joint.

Female mating member 234 is placed between flanges 192, 246 so that acorner opening 238 of female mating member 234 is correspondinglyadjacent to openings 260, 264 of corner members comprising in partflanges 192, 246. Corner bolt 250 is inserted through openings 260, 264and corner opening 238, mated with corner nut 256, and corner bolt 250and corner nut 256 are tightened. In other embodiments of the presentinvention, female mating member 234 may be configured to not be placedbetween flanges 192, 246, but rather, on the opposite side of eitherflange 192 or flange 246. In other embodiments of the present invention,female mating member 234 may be configured to have a U-shaped tab 242that may surround flanges 192, 246, rather than be placed betweenflanges 192, 246.

In this embodiment of the present invention, only a tab 242 of femalemating member 234 is positioned directly between flanges 192, 246. Ledge240 and body 244 typically project perpendicularly outwards beyondflanges 192, 246. In some embodiments of the present invention, femalemating member 234 may be rotatable about corner bolt 250. As there maybe some gap between flanges 192, 246, in some circumstances it may bepossible that female mating member 234 rotates sufficiently about cornerbolt 250 so that ledge 240 and body 244 enter the gap between flanges192, 246 and female mating member 234 will be subsequently difficult toretrieve. One potential advantage of ledge 240 is that ledge 240restricts ledge 240 and body 244 from entirely entering gaps betweenflanges 192, 246 smaller than the depth of ledge 240.

In this embodiment of the present invention, as discussed above, ledge240 depends from body 244 by an offset so that ledge 240 is aligned withone side of body 244. Accordingly, where female mating member 234 ispositioned between flanges 192, 246 so that body 244 is inwardly offset(instead of outwardly offset), this offset between ledge 240 and body244 causes body 244 to only outwardly project beyond flanges 192, 246 ina single axis. One potential advantage is that when female mating member234 is connected to duct joint 132 in this fashion, female mating member234 may be positioned to outwardly project beyond duct joint 132entirely within the footprint of the “top” panel of duct sections 104,106, as defined above, and accordingly, it may be possible forinterconnected duct sections 104, 106 to lie flat on their “sides”. Thismay be advantageous by allowing portions of duct with installed femalemating members to lie flat on their sides during storage or transport,and to be potentially stackable.

With reference to FIG. 11A, FIG. 11B, FIG. 11C, and FIG. 11D, a malemating member 288 is depicted corresponding to one embodiment of thepresent invention. Male mating member 288 may be formed from sheet metalusing methods well-known in the art such as stamping. Male mating member288 comprises a body 290, a hook 292, and a plate 300 which may be equalin width to body 290 and which may depend from body 290 along its entirewidth to form a approximate ninety-degree angle therebetween.

Body 290 may be generally rectangular in shape and positionedtherewithin is a generally rectangular opening 302. Opening 302 may beapproximately centered along the width of body 290 and positioned alongthe length of body 290 at an offset towards the side of body 290 whichis opposite the side of body 290 from which the plate 300 depends. Inthis embodiment of the present invention, hook 292 may be formed from atab of sheet metal corresponding to opening 302 and may depend from body290 along one width of the tab. In other embodiments of the presentinvention, hook 292 may be separately formed and connected to body 290,in such embodiments, opening 302 may therefore not need to be formed inbody 290.

Hook 292 may be generally rectangular in shape and may primarily lie ina plane parallel to the plane in which body 290 lies. The side of hook292 that is furtherest removed from plate 300 depends from body 290along the entire width of hook 292 by means of an approximateninety-degree bend 304 in hook 292. Bend 304 causes hook 292 to beoffset from body 290 by the approximate thickness of body 286 of femalemating member 276. Hook 292 may be constructed to be smaller thanopening 280 of female mating member 276 as hook 292 is intended to passthrough opening 280 during combined use of male mating member 288 andfemale mating member 276, as described in more detail below.

In some embodiments of the present invention, hook 292 may include afriction pad 294 so that female mating member 276 and male mating member288 are more firmly interconnected when used together, as described inmore detail below. Friction pad 294 may be constructed to be a shallowtriangular protrusion on the face of hook 292 that faces body 290.

Plate 300 may be equal in width to body 290 and depend from body 290along its entire width to form an approximate ninety-degree angletherewith. Plate 300 may be generally rectangular in shape and may havepositioned therewithin a rod opening 298. Rod opening 298 may beapproximately centered in plate 300 and may be configured to allow athreaded rod (not shown) to pass therethrough. Plate 300 projects awayfrom the plane in which body 290 lies in the direction opposite thedirection in which hook 292 is offset relative to body 290. Gussets 296positioned across the bend between plate 300 and body 290 may beoptionally included to strengthen the bend between plate 300 and body290.

With reference to FIG. 12C, to interconnect male mating member 288 witha threaded rod 314, a first end of threaded rod 314 is passed throughrod opening 298. Nut 316 is then mated with threaded rod 314 so thatmale mating member 288 abuts nut 316 from the side of nut 316 oppositethe first end of threaded rod 314. Optionally, a second nut (not shown)may be mated with threaded rod 314 and positioned to abut male matingmember 288 on the side of male mating member 288 opposite nut 316. Itmay be advantageous to abut male mating member 288 from both sides withnut 316 and the second nut (not shown) so as to affix male mating member288 more firmly to threaded rod 314.

With further reference to FIG. 12C, female mating member 276 and malemating member 288 may be interconnected. To do so, female mating member276 and male mating member 288 are brought into close proximity so thathook 292 passes through opening 280. Once body 244 of female matingmember 276 abuts body 290 of male mating member 288, female matingmember 276 and male mating member 288 may be shifted in oppositedirections so as to insert body 244 of female mating member 276 betweenhook 292 and body 290 of male mating member 288 until bend 304 abuts, oralmost abuts, a side of opening 280. In some embodiments of the presentinvention, such as if hook 292 includes friction pad 294, body 244 offemale mating member 276 may need to be tapped in with a hammer to forcebody 244 between hook 292 and body 290 of male mating member 288.

In the immediately above-described embodiment of the present invention,female mating member 276 has opening 280 and male mating member 288 hashook 292. In another embodiment of the present invention, the locationof opening 280 and hook 292 may be interchanged so that female matingmember 276 instead has a hook that passes through a correspondingopening of male mating member so as to interconnect the female matingmember and male mating member. In other embodiments of the presentinvention, other means of connection well known in the art may beemployed to connect male mating member and female mating member, such asbolts, rivets, and ties.

Returning to FIG. 1, in this embodiment of the present invention, eachof threaded rods 144, 146, 148, 150 are anchored at a first end (notshown) by means well-known in the art to elevated supports (not shown),such as overhead pipes or the surfaces of ceilings. threaded rods 144,146, 148, 150 terminate at a second end that is interconnected withattachment members 136, 138, 140, 142, each attachment member comprisinga female mating member and a male mating member. With reference to FIG.12C and the description above, threaded rods 144, 146, 148, 150interconnect with a male mating member of each of attachment members136, 138, 140, 142. With reference to FIG. 12C and the descriptionabove, each male mating member of each of attachment members 136, 138,140, 142 is in turn interconnected with a female mating member of eachof attachment members 136, 138, 140, 142.

Duct joint 130 may include the female mating members of attachmentmembers 136, 138, each female mating member being interconnected withthe top corners of the flanges of duct joint 130, as described above.Duct joint 134 similarly may include the female mating members ofattachment members 140, 142, each female mating member beinginterconnected with the top corners of the flanges of duct joint 134, asdescribed above. As duct sections 102, 104, 106, 108 are interconnectedat duct joints 130, 132, 134 to form a portion of duct 100, the portionof duct 100 is therefore suspended from elevated supports (not shown) bymeans of this configuration.

In some embodiments of the present invention, the first ends of threadedrods 144, 146, 148, 150 may be anchored to the same support, but inother embodiments, the first ends of threaded rods 144, 146, 148, 150may be anchored to one or more supports (e.g. different overhead pipes,or a combination of overhead pipes and surfaces of a ceiling).

In the embodiment of the present invention depicted by FIG. 1, duct 100is relatively positioned below the supports. In other embodiments of thepresent invention, duct 100 may be relatively positioned differently,for example, to the side of the support or above the support.Correspondingly, female mating members, and by implication attachmentmembers more generally, may be positioned at various corners of a ductjoint. For example, while the embodiment of the present inventiondepicted by FIG. 1 depicts attachment members positioned at the topcorners of a duct joint, in other embodiments of the invention,attachment members may be positioned at the bottom corners of a ductjoint, the side corners of a duct joint, or opposing corners of a ductjoint. Separate duct joints may have attachment members positioned atdifferent corners.

In the embodiment of the present invention depicted by FIG. 1, ductjoint 132 is not supported with attachment members connected to means ofsupport as it may not be necessary to support duct 100 at every ductjoint. FIG. 1 depicts duct 100 supported at every 2^(th) duct joint, butin other embodiments of the invention, duct 100 may be supported atevery N^(th) duct joint, where the upper bound for N may be determinedby the skilled person in the art in view of considerations such as theweight and structural integrity of duct 100. In other embodiments of theinvention, duct 100 may also be supported at irregularly spaced ductjoints, again as determined by the skilled person in the art in view ofconsiderations such as the weight and structural integrity of duct 100.

In the embodiment of the present invention depicted by FIG. 1, each ductjoint includes either no female mating members or two female matingmembers. In other embodiments of the invention, a given duct joint mayinclude different numbers of female mating members. For a rectangularduct, a given duct joint may include between zero and four female matingmembers, each of which may or may not be in fact connected to means ofsupport.

In the embodiment of the present invention depicted by FIG. 1, onlymeans of supporting duct 100 by means of female mating membersinterconnected with a flange are shown. In other embodiments of thepresent invention, other prior art means of supporting duct 100 such ascradle bars may be used in combination with the methods and apparatus ofthe present invention.

The use of hook 292 and opening 280 to interconnect female mating member276 and male mating member 288 may be advantageous in somecircumstances. For example, with reference to FIG. 1, one method ofinstalling duct sections 102, 104, 106, 108 is to first interconnect atground level duct sections 102, 104, 106, 108, including the femalemating members of attachment members 136, 138, 140, 142. Separately,corresponding male mating member of attachment members 136, 138, 140,142 may be attached to the second ends of threaded rods 144, 146, 148,150 in a loose fashion that allows the male mating members to shift.Interconnected duct sections 102, 104, 106, 108 may then be elevated sothat the connected female mating members are approximately at the sameposition as each corresponding male mating member. It is then possibleto interconnect each pair of female mating member and male mating memberby making precise adjustments to interconnect each pairing in series, asopposed to simultaneously positioning all four pairings.

FIG. 12A and FIG. 12B depict alternative illustrative means to connect afemale mating member to existing means of support without the use of amale mating member.

FIG. 12A shows the use of a length of steel wire 306, anchored at oneend to a support (not shown), and the other end interconnected withfemale mating member 276 by passing steel wire 306 through opening 280,and connecting steel wire 306 back to itself with a lock 308. A ductsection may be connected to female mating member 276 and thereforesupported by steel wire 306 as described above.

FIG. 12B shows the use of a steel strap 310, anchored at one end to asupport (not shown), and the other end interconnected with female matingmember 276 by means of a connecting bolt 312 and a nut 318. connectingbolt 312 is passed through an opening (not shown) in steel strap 310 andopening 280 of female mating member 276, mated with nut 318, andconnecting bolt 312 and a nut 318 are tightened so as to interconnectfemale mating member 276 and steel strap 310. A duct section may beconnected to female mating member 276 and therefore supported by steelstrap 310 as described above.

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually incorporated by reference.

While the foregoing invention has been described in some detail forpurposes of clarity and understanding, it will be appreciated by oneskilled in the art, from a reading of the disclosure, that variouschanges in form and detail can be made without departing from the truescope of the invention.

What is claimed is:
 1. An attachment member for suspending an airtransport duct from a ceiling element of a building structure, said airtransport duct including a duct section having two terminal open endsand a flange disposed around each of said open ends for abuttingconnection to the flange of an adjacent duct section of said duct, eachsaid flange comprising a first receiving channel adjacent to a firstcorner thereof and a second receiving channel that is generallytransverse to said first receiving channel and adjacent said firstcorner, said attachment member comprising: an insertable corner memberpositionable into said first receiving channel and into said secondreceiving channel, said insertable corner member being attachable to atleast one of said first receiving channel and said second receivingchannel by means of a load-bearing connection therebetween, such thatsaid insertable corner member is capable of supporting a predeterminedportion of a weight of said duct; and a connecting member securable tosaid insertable corner member and to said ceiling element of a buildingstructure for suspending said duct from said ceiling element of abuilding structure, said connecting member including first and secondmating members that are connectable to one another, said first matingmember providing a first connector for securing said connecting memberto one of said duct sections of said duct, said second mating memberproviding a second connector for securing said connecting member to saidsupport; wherein said first mating member includes a slot and saidsecond mating member includes a hook configured for sliding engagementwith said slot; wherein said first connector of said first mating memberis a flat tab at a terminal end thereof and having an aperturetherethrough; wherein said second mating member is generally L-shapedand said second connector of said second mating member is a surface at aterminal end thereof and having an aperture therethrough, said surfacebeing generally transverse to said flat tab of said first mating memberwhen said first and second mating members are connected to one anotherand being transverse to a direction of said sliding engagement of saidhook and said slot; and wherein said hook of said second mating memberprovides a friction pad thereon for press-fit connection of said firstand second mating members to one another.
 2. The attachment memberaccording to claim 1, wherein said flat tab of said first mating memberbeing capable of attachment to said insertable corner member.
 3. Theattachment member according to claim 2, wherein each said insertablecorner member is generally L-shaped, wherein each said flange has flangeportions thereof that are correspondingly adjacent to peripheral edgesof said terminal open ends of said duct section, with a first pair ofimmediately adjacent flange portions at said peripheral edges of eachterminal open end of said duct section forming a first gap located atsaid first corner of each said flange, said first and second receivingchannels of each said flange being respectively located in saidimmediately adjacent flange portions, and wherein each said insertablecorner member, when positioned into said first and second receivingchannels of each said flange, occupies said first gap and therebypresents a connecting surface for said flat tab of said first matingmember.
 4. The attachment member according to claim 3, wherein each saidconnecting surface provides an aperture therethrough for receiving afastener that is likewise receivable by said aperture of said flat tabof said first mating member to thereby secure each said insertablecorner member to said first mating member.
 5. The attachment memberaccording to claim 4, wherein said first mating member provides ashoulder adjacent said flat tab for abutment against at least one ofsaid flanges of said duct section when said first mating member issecured to at least one of said insertable corner members as aforesaid,wherein rotation of said first mating member relative to said ductsection is thereby arrested.
 6. The attachment member according to claim5, wherein said first mating member provides a generally flat planarportion in which said slot is disposed, with said flat tab stepwisedepending from said flat planar portion to thereby form said shoulder.7. The attachment member according to claim 6, wherein said flat tab isoffset from a longitudinal axis of said flat planar portion, such thatwhen said first mating member is secured to at least one of saidinsertable corner members as aforesaid, said first mating member iscapable of being positioned so that said first mating member does notextend laterally beyond an adjacent sidewall of said duct section.